This invention relates to a protection mask, in particular for underwater use.
As is well known, the normal underwater masks essentially comprise an optical surface provided with a rubber-coated rim which seals against the user's face and extends sufficiently to contain the nose, without however preventing it from being squeezed between the fingers to close it hermetically, so as to enable the user to effect the necessary compensation as the depth of immersion changes. In this respect, compensation is an essential operation for adequately counter-balancing the external pressure to prevent collapse of the eardrum. Although the aforesaid masks are reliable and are commonly used, they present drawbacks which are well known to the expert and will therefore be only briefly mentioned.
To breath in and out, the user has to hold in his mouth (retaining it between his teeth) a nozzle, upstream of which there is provided a feeder (low pressure reducer), the mass of which is large as it consists of inoxidizable metal re resist corrosion. Respiration through the mouth is not natural and the discomfort deriving therefrom is further intensified in that cylinder air is much drier than atmospheric air. The mouth engages in this manner cannot be used to activate other instruments, for example to voice-activate the remote voice transmission instruments. The protection offered by such masks against water, against cold and against the effects of pressure is limited to the few covered parts. The seal which such masks offer of often more theoretical than practical in that the mask gaskets are required to perform the difficult task of sealing against those regions of the face which are extremely special both for their delicacy, for their very variable shape from person to person, and for their mobility (facial action is very intense).
To solve the aforesaid drawbacks, consideration could be given to using masks having a face shield covering the entire face. For example consideration could be given to using (after suitably adapting the connectors for the respiration devices) the protective masks described in U.S. Pat. No. 5,080,092 and IT 1 215 684, but currently this is not possible mainly because such masks (commonly known as "large face shield" masks because they cover the entire face of the user) prevent access to the nose for the compensation operation. The use, under variable pressure conditions, of masks which do not allow this compensation clearly lead to eardrum rupture.
The object of this invention is therefore to obviate the aforesaid drawbacks by providing a "large face shield" mask which enables compensation operations to be effected, while being able to be used under variable external pressure and in particular in an underwater environment.
Using a mask of the invention, ie a "large face shield" mask, which at the same time enables the compensation operations to be effected results in the overcoming of all the problems which afflict current underwater masks and which have merely been summarized heretofore in that they are numerous and are well known to the expert of the art in addition to all who practice underwater activity.
These objects are attained by an underwater mask in accordance with claim 1, to which reference should be made be brevity. During normal use the means for compensating the pressure within the ear duct, and comprising at least one protuberance, can be positioned below the user's nostrils so as not to hinder free air inflow and outflow. When compensation becomes necessary, by utilizing the elasticity and deformability of the seal gasket the face shield is suitably moved relative to the user's face so that said at least one protuberance is rested against the user's nostrils by a movement from the bottom upwards relative to the user's face, so as to seal them hermetically and allow compensation. It is important to note that the invention is based mainly on the intuition that to effect compensation it is not essential to squeeze the nose (an operation which is sometimes painful because of the presence of mucous within the nostrils and in any event always annoying and irritating for the nose) but is also possible by simple closure achieved by barring the nostril holes from the outside. The method by which closure is achieved by simple barring, ie by applying occluding bodies from the bottom upwards to the nostrils, is inventive in that it is contrary to the teaching of closing the nostrils by squeezing, which has always been accepted as the most natural, and hence unquestioned in the art. Consequently the invention goes against the technical prejudgements of the art in that in the underwater sector it has never been considered that the simple application of occluding bodies to the nostrils could achieve a sufficiently valid closure for the compensation operations to be adequately effected. A mask of "large face shield" type can therefore be used in the presence of pressure variations and in particular under water, with the following further advantages:
The user can breathe in and out in a natural manner, ie mainly through the nose and if necessary also through the mouth in the case of breathlessness. Mucous material in the throat is no longer subject to drying by the effect of the dry air fed in, because the nose is able to compensate in a natural manner for ny decreased air humidity.
The mouth is freed of the nozzle, and the jaws are no longer burdened by the weight of the feeder and nozzle and hence the mask can be worn for several hours without excessively tiring these body parts.
The feeder and nozzle weight are supported by the face shield and are transmitted to the user's face by the seal gasket which by resting on a very wide and regular portion of the face can create an excellent seal without excessive pressure. Possible further devices (such as a phonic device) can therefore be applied to the face shield without any problem.
The feeder feeds air into the mask such that the pressure within the mask is equal or proportional to the external pressure. By suitably adjusting the device for evacuating the air breathed out by the user, the pressure within the mask can be maintained within a range of optimum values for the gasket seal and for user comfort. This avoids the annoying and sometimes painful phenomenon of the mask squeezing against the user's face when the external pressure increases.
If, notwithstanding all this, water should manage to penetrate into the mask, it is necessary merely to adjust the feeder so that it feeds an additional air flow at a pressure sufficiently higher than the external pressure such that the water which penetrates is expelled through the device for evacuating the air breathed out by the user, together with the additional air. In traditional underwater masks this is not possible because the feeder feeds directly into the user's mouth, and devices for evacuating the air breathed out by the user are not provided.
As the mouth is no longer engaged to retain the nozzle, it can be used to speak in a natural manner and hence for communication if the mask is also provided with voice remote transmission means. The mask of the invention can be modified for communication with all the advantages deriving therefrom.
By isolating the forehead, the eyes, the nose, the mouth and the chin from the external environment, the mask of the invention offers effective protection for these parts of the body against cold, against water, against salinity, and against possible contaminant substances dissolved in the water. In this respect, such effective protection is unattainable with traditional underwater masks, which are substantially limited to covering and hence protecting only the eyes and nose.
By acting on a tendentially large surface, the seal gasket provides excellent sealing without generating lines or reddening on the skin in those regions on which it rests.
The protective mask of the invention can also be used in variable pressure environments other than underwater, for instance at high altitude where compensation is necessary and where it would be very advantageous to use "large face shield" masks because of their good protection characteristics. From the aforegoing it is also apparent that the mask of the invention can also be used without problems as a terrestrial protective masks. As the mask of the invention can be used in water, on the ground and at high altitude, it has a flexibility of use such that the number of models can be reduced, to the extent of making it particularly economical and attractive to the market, especially the military market which with a single mask could cover all requirements.
One embodiment of the mask of the invention is described hereinafter by way of non-limiting example with reference to the accompanying figures. The described embodiment relates in particular to a protective mask for underwater use.